DE102018205894B4 - Objective changing device for a microscope system and method for adjusting an objective - Google Patents

Abstract

Objective changing device (2) for a microscope system (1) with
a lens transfer element (3) with at least one lens holder (4) for holding a lens (6) provided with an adapter (7), wherein
the lens transfer element (3) is designed to deliver a selected active lens (6) to a transfer position (CP) in a controlled manner, wherein
an objective axis (61) of the active objective (6) in the transfer position (CP) does not coincide with the optical axis (11) of the microscope system (1),
a transfer device (5) which is adjustable in the direction of the optical axis (11) of the microscope system (1) and which can be brought into contact with the adapter (7) of the active objective (6) and which is designed to transport the active objective (6) along a transport path (TS) in a transport direction (TR) orthogonal to the optical axis (11) of the microscope system (1) between the transfer position (CP) and a working position (WP) in the optical axis (11) of the microscope system (1);
wherein the transport path (TS) is shorter than the extension of the lens holder (4) in the transport direction (TR), so that at least areas of the adapter (7) of the active lens (6) located at the working position (WP) are still within the extension of the lens holder (4).

Description

The invention relates to an objective changing device for a microscope system and a method for moving an objective with an adapter into the optical axis of a microscope system.

Many modern microscopy techniques require highly precise positioning of the microscope objectives used for image acquisition. For example, when acquiring stacks of individual images arranged one after the other along the optical axis of the microscope system (image stacks, z-stacks), an active objective used for image acquisition must be capable of highly dynamic and precise movement. In order to perform the microscopy process on an object with different magnifications and resolutions, switching between different objectives is also necessary.

The objectives mounted on a microscope are typically arranged and held in a nosepiece. The objective lens currently being used or intended for image acquisition is in a working position, while the other objectives held in the nosepiece are pivoted out of the working position.

When focusing the objective currently in the working position, the objective nosepiece, along with any currently unused objectives, is moved in the focus direction—commonly referred to as the Z-direction. Thus, with each focusing operation, the entire mass of all currently unused objectives, as well as the mass of the objective nosepiece, is moved. This results in high holding and acceleration forces and requires a robust design of the drive system and guides. The large mass to be moved leads to high mechanical stress and preload on the drive train, promoting adverse drift effects. Stick-slip effects are also promoted, increasing susceptibility to vibration and wear.

The eccentric center of gravity of the objective nosepiece, i.e., located outside the optical axis of the microscope system, exerts unfavorable leverage on the guides of the objective nosepiece. If the objective nosepiece contains different objectives, changing the objectives also leads to a shift in the center of gravity and thus to a changed load situation. This also negatively impacts positioning accuracy, the preservation of the image section, and the accuracy of the objective movements.

There are known solutions from the state of the art in which not the entire objective turret is included in the focusing movement.

So in the WO2004/077123 A2 A microscope system is described that has an objective transfer element with a number of interchangeable objectives. A selected objective can be brought into the optical axis of the microscope system using the objective transfer element. Each of the objectives can be moved coaxially with the optical axis independently of the other objectives. Using an actuator element, the objective located in the optical axis can be focused independently of the other objectives and without moving the objective transfer element. A disadvantage is that an insufficiently precise adjustment of the selected objective into the optical axis cannot be compensated for, or can only be compensated for, using passively acting adjustment means.

The DE 10 2007 058 341 A1 relates to an objective changing system for an optical measuring device, in particular a microscope device, having at least one objective which is mounted in a supported holding device and can be moved by means of a displacement device between a use or working position, in which the at least one objective can be displaced coaxially to an optical measuring axis for focusing, and a non-use position.

Further technical solutions are available, for example, from WO 2012/097191 A 2 and the DE 10 2015 221 040 A1 The invention described therein relates to a microscope comprising an objective changing device with a magazine for accommodating a number of objectives at respective magazine positions and with an objective receptacle designed to accommodate an objective and arranged in an optical beam path of the microscope. The microscope is characterized by an objective for transporting a selected objective and having an objective holder, wherein the transport between its magazine position, which is delivered to a transfer position, and the objective receptacle takes place by means of an objective delivery device. During the transport of the objective, the objective receptacle remains in the optical beam path.

The lens changing devices known from the state of the art either have the disadvantages explained above with regard to the comparatively low precision and repeatability or long delivery paths of the lenses are required.

The invention is based on the object of providing a possibility for precise and repeatable To propose the delivery of at least one selected active lens to a desired position and thereby reduce the disadvantages of the prior art.

The object is achieved by an objective changing device for a microscope system and a method for advancing an objective provided with an adapter and held in an objective holder according to the independent and subordinate claims. Advantageous further developments are the subject of the dependent claims.

The objective changing device for a microscope system has an objective transfer element (hereinafter also referred to as transfer element) with at least one objective holder for holding an objective provided with an adapter. The objective transfer element is designed to controllably advance a selected active objective to a transfer position. The objective has an optical axis, which is also referred to below as the objective axis. In the transfer position, the objective axis of the active objective does not coincide with the optical axis of the microscope system. Furthermore, the objective changing device has a transfer device which is adjustable in the direction of the optical axis of the microscope system and which can be brought into contact with the adapter of the active objective. The transfer device is designed to transport the active objective along a transport path between the transfer position and a working position in the optical axis of the microscope system in a transport direction that is essentially orthogonal to the optical axis of the microscope system.

According to the invention, the transport path is shorter than the extent of the objective holder in the transport direction, so that at least areas of the adapter of the active objective located at the working position are still within the extent of the objective holder. The length of the transport path is measured as the shortest distance, for example as an orthogonal offset, from the transfer position to the working position. The adapter is also considered to still be in the objective holder if, in a plan view from the direction of the optical axis of the microscope system, at least areas of the adapter of the active objective located at the working position are still within the extent of the objective holder. It is therefore possible to lift the objective with the adapter out of the objective holder.

Distances between the objective axis of an objective in the transfer position and the optical axis of the microscope system are preferably a few millimeters, for example, 1, 2, 3, 5, 10, 20, or 30 millimeters, depending on the objective diameter. The distance is advantageously, for example, one-tenth, one-fifth, one-quarter, one-third, half, or at most three-quarters of the objective diameter.

In an advantageous embodiment of the objective changing device, the transfer device can be moved coaxially to the optical axis of the microscope system. To remove the objective from the objective holder, the transfer device is designed to lift the active objective. For this purpose, the transfer device can be moved in the direction of the optical axis, for example, by a controlled motor.

The following assumes that a lens is always equipped with an adapter. From a purely mechanical perspective, the processes of moving the lens to the transfer position and the working position could also be performed using the adapter alone.

An important aspect of the lens changing device is the precise and repeatable positioning of the active lens in the optical axis of the microscope system. For this purpose, the lens mount is provided with adjustment surfaces to which the active lens can be attached using the adapter's contact surfaces designed to engage the adjustment surfaces. The contact surfaces and adjustment surfaces are designed and manufactured with such precision in terms of their shape, dimensions, and accuracy that an active lens, with its contact surfaces in contact with the adjustment surfaces, is aligned parallel to the optical axis of the microscope system. The lens axis of the active lens then coincides with the optical axis of the microscope system.

Position reproducibility is achieved through the contact surfaces and adjustment surfaces. These form, for example, a three-point support or a three-point contact. Such positioning can be achieved, for example, using a dovetail element aligned with the optical beam path and by clamping the contact surfaces and adjustment surfaces against each other using the gripper.

To achieve an ideal three-point clamping, a conical base of the adapter, for example a dovetail ring, can be designed with sub-segments so that only two sub-segments (contact surfaces) engage with the respective adjustment surfaces and define contact points. A third contact point can be realized via a spring element in the gripper, which acts as a animal surface and is guided against another contact surface of the adapter.

Instead of a dovetail ring, three balls can also be provided at the bottom of the adapter, which protrude slightly downwards and laterally. This allows for a three-point support on one surface of the lens mount and, at the same time, a three-point lateral support on the lens mount.

In a further possible embodiment of the lens changing device according to the invention, the adjustment surfaces are designed as inclined surfaces, for example in the form of horizontal V-grooves. The adjustment surfaces can be distributed at 120° to each other and to the gripper's contact point.

The lens transfer element can be designed, for example, as a revolver, a strip magazine, a chain magazine, a conveyor belt, or a slider. Transfer from a shelf magazine using a robot arm is also possible. The lens transfer element can be loaded either manually or by an automated loading system, which can provide an additional lens magazine.

In one embodiment of the lens changing device, the lens transfer element has at least one lens holder configured as a fork. A fork-shaped lens holder allows, for example, movement of the lens in the transport direction without having to completely lift the lens out of the lens holder, for example, parallel to the optical axis.

A forked lens mount can be U-shaped with essentially parallel legs. This design is used, for example, in upright arrangements that have an additional retaining element that securely holds an adapter even during rotational movements of the transfer element. In other designs, the forked lens mount can be slightly closed, meaning that the ends of the legs are closer together.

In this case, it is advantageous if at least the ends of the legs are spring-loaded, so that an adapter can be inserted into or removed from the lens mount by slightly bending the ends. When the lens and adapter are in the lens mount, the ends of the legs rest against the adapter and thus hold it firmly in the lens mount. For this purpose, it is advantageous if the outer dimensions of the adapter correspond to the inner dimensions of the respective lens mount in such a way that the adapter - and with it the lens - is accommodated in the lens mount with only slight play. This design is suitable, for example, for inverse arrangements. In this case, an additional holding element is not necessary.

The lens changing device can be designed for both an inverted and an upright arrangement of the active lens. In an inverted arrangement, the active lens and the transfer device are located below the object plane in which a sample to be observed can be placed (sample plane). The active lens is directed from below towards the object plane and sits on the lens holder. In an upright arrangement, the active lens and the transfer device are located above the object plane. The active lens hangs in the lens holder. For this purpose, the lens holder can have a holding element on which the collar of the respective lens adapter rests. Generally speaking, each lens holder has a locking device, the effect of which locks the adapter in the lens holder at least in one direction parallel to the optical axis. This locking device can be the aforementioned holding element in an upright arrangement or an edge of the lens holder in an inverted arrangement, on which the adapter rests with a collar.

If the lens changing device is designed as an upright arrangement, the lenses can, in one possible embodiment, be inserted from a lateral direction into a gap between the respective lens holder, for example again designed in a fork-shaped manner, and the locking device, for example the additional holding element, in order to load the transfer element acting as a magazine.

The lens mount can be designed as a spring-loaded fork, as described above. In a further embodiment of the invention, the lens mount can be approximately U-shaped, and the additional holding element can be designed as a spring-loaded fork joint.

When inserting the lens, using the same adapter as in the inverted configuration, the ends of the fork's legs are opened by the lateral pressure exerted by the adapter collar. Due to the spring-loaded design of the fork, they are retracted around the collar once the lens reaches its final position. The lens is thus securely held during movement of the transfer element.

Alternatively, the forks can be designed so that the lens adapter is not inserted through the opening of the fork, but rather transversely to the plane in which the fork extends with its legs.

For this purpose, the respective adapter is moved via an additional, spring-loaded holding element, for example, a spring-loaded catch. This additional holding element is first pushed sideways, for example, and then engages a correspondingly shaped structure of the adapter. The spring force of the additional holding element is advantageously dimensioned such that the mass (or the resulting weight) of the respective lens and, if applicable, the respective masses of all other usable lenses, are held against gravity and possible acceleration forces. A drive used to move the transfer device in the direction of the Z-axis (Z-drive) must be able to overcome this holding force.

Coarse and/or fine drives, stepper motor drives, and/or piezo drives can be used as Z-drives. The transfer device can be mounted on a stand. Precise and low-friction guidance of the transfer device moving in the Z direction can be achieved, for example, using sliding, ball, and/or roller guides.

One or more switchable electromagnets can also be used to hold the respective lenses and/or adapters in the lens mount, transfer element, or transfer device. These electromagnets are switched off once the adapter is clamped.

Alternatively, permanent magnets can be provided on the adapter and transfer element and designed so that their opposite poles face each other and attract each other. This magnetic force can be canceled out by a translational movement perpendicular to the optical axis of the microscope system or a rotational movement, for example, around the optical axis of the objective. In a further embodiment of the invention, additional magnets can be arranged which, after a translational movement or rotational movement, face the magnets of the adapter with the same polarity. The opposing magnetic poles cancel out the holding force or additionally repel each other.

In order to capture image data with the active lens, it must be brought into the beam path of the microscope system. The lens axis of the active lens and the optical axis of the microscope system must coincide. For this purpose, in an advantageous embodiment of the lens changing device, the transfer device has a gripper designed to engage with the active lens. The gripper can be moved in a controlled manner in the transport direction. In addition, there is a lens holder or a lens holding surface which is designed as a transport path for the active lens moved by the gripper and for holding the active lens in the optical axis of the microscope system. By means of the transfer device, in particular by means of the gripper, the adapter can be moved with its contact surfaces against the adjustment surfaces.

The following drives can be used for the lateral movement of the gripper: motor with spindle drive, cam disc, belt drive, cable pull, rack and pinion drive, SMA/SMA wire drive (SMA = shape memory alloy, smart metal alloy), piezo drives, adjustable wedges, nut-spindle pairings or other actuators for converting rotary into linear movement.

To enable movement of the active objective in the Z direction along the optical axis of the microscope system, a mechanical element, such as a motor-driven lever, can act against the spring force of the holding element and push the fork open until the objective is freely movable in the Z direction. The ends of the fork legs can be guided in grooves to hold the objective in the transfer element against gravity.

The objective changing device can be combined with an optical element that can be moved into the beam path of the microscope system as needed. In one possible embodiment of the invention, the optical element is a motorized DIC slider (DIC = differential interference contrast). To enable the optical element to be moved into or out of the beam path, a shaft for the optical element, in particular for the DIC slider, is provided in the adapter. Each objective can be assigned its own optical element, which remains on the respective objective or adapter even when the active objective is returned to the transfer element. In such an embodiment, only one drive is advantageously provided for all optical elements. This drive only ever accesses the optical element of the active objective, positions it sensitively for the respective application, for example, a DIC application, or retracts the optical element from the beam path when not in use. The optical element is explained in more detail using the example of a DIC slider.

The DIC slider can be permanently attached to the adapter and remain attached regardless of its current use. It is also possible for the DIC slider to be inserted into and removed from the slot of the currently active lens. For the purposes of this description, a removable DIC slider is not permanently attached to the adapter.

In further embodiments of the invention, a slide is provided that can be moved into or out of the optical axis of the microscope system. The DIC slider can be moved into or out of the optical axis of the microscope system by means of the slide. For this purpose, the slide can be motor-driven and controllable. In further possible embodiments, it can also be designed to be manually movable into or out of the beam path of the microscope system and, for example, be attached to the transfer device.

The carriage can be equipped with at least one magnet, by means of which a releasable holding force can be generated between the carriage and the DIC slide. This releasable holding force can be generated, for example, by means of controllable electromagnets and/or permanent magnets. If permanent magnets are used, wipers are required to overcome the holding force when necessary and separate the carriage and DIC slide from each other.

To position or remove the DIC slider from the beam path of the active lens, a carriage with a magnet, for example, moves to the coupling point of the DIC slider and docks onto it. Alternatively, another coupling mechanism can be used between the carriage and DIC slider, e.g. spring-loaded elements, electrically switchable magnets, or mechanically acting coupling mechanisms. After the DIC slider has been returned to the adapter shaft, the coupling must be released again. In the case of permanent magnets, the wiper is required to counteract the holding force of the magnetic coupling between the DIC slider and the magnet on the carriage by holding the DIC slider in its position in the shaft while the carriage moves back. This wiper can be mounted on the gripper, which can also have the function of pushing the adapter or the adapter with the lens back towards the transfer element when the gripper is opened.

An advantage of the lens changing device according to the invention is that only a single lens is located on the transfer device, and it needs to be advanced, i.e., moved, in the Z direction. This means that only the mass of the active lens needs to be moved with the drive train. The effects of inertia and the stick-slip effect are reduced. As a result, the moving lens can be decelerated and accelerated quickly, thus enabling a faster focusing process. The lens changing device according to the invention therefore has significantly improved dynamic properties compared to prior art solutions.

A further advantage is that the lower mass increases the natural frequency of the lens changing device, which reduces the vibration amplitudes for the same excitation energy and significantly reduces susceptibility to building vibrations, for example. The resulting lower dynamic deviations lead to improved resolution of a captured image over the time of image acquisition. In contrast, a combination of high mass and low rigidity, such as that resulting from the installation space arrangement of known lens changing devices, results in a low natural frequency.

The objective changing device according to the invention can be used in the entire field of microscopy with a wide variety of objectives, from wide-field and confocal microscopes to light-sheet microscopy, but also with a white light interferometer.

An adapter for use with a lens in a lens changing device according to the invention is described below.

The adapter has a collar for resting on the lens mount, by means of which the adapter is or can be held in the lens mount. It also has projections and/or indentations that correspond to correspondingly shaped guides on the transfer device. Flattened areas on the outer circumference of the adapter are also understood to be indentations of the adapter. For example, one or more lateral flattened areas on the adapter and lateral guide surfaces on the transfer device can be present. The projections and/or indentations and the corresponding guide surfaces ensure that the alignment of the adapter is maintained during transport along the transport path. At least one of the projections and/or indentations of the adapter can have a contact surface.

Ensuring the relative alignment of the adapter is important, for example, for the use of the DIC slider and also allows electrical contact with the adapter and/or the transfer of media to or from the adapter. Maintaining the orientation of the adapter in the transfer element can be achieved, for example, via guide pins in the transfer element and grooves in the adapter's flange.

In another possible embodiment of the objective changing device according to the invention, a transfer point for media in liquid or gaseous form, as well as mixtures (aerosols, gels), can be provided to the objective and/or the adapter. This transfer point can be used, for example, for a preferably automated immersion via the objective or for suctioning off immersion fluid, as well as for tempering the objective.

The transfer and/or receipt of media can be achieved using appropriately designed supply and discharge lines and compatible coupling elements. Pumps, sensors, and media reservoirs can also be provided to enable media exchange. A control unit can be connected to the pumps and/or sensors to regulate or control the media exchange.

The advantage is that the transfer point for supplying and/or removing the medium does not have to be attached to a transfer element such as a rotating revolver, for example, where the rotational movement would be restricted and a possibly complex and expensive rotary feedthrough would have to be provided.

An adapter can be equipped with a lens and used in a microscope system.

Compared to known solutions from the prior art, a lens changing device according to the invention has several advantages.

The active objective lens is thus moved parallel to the optical axis of the microscope system, yet remains slightly offset from the optical system's beam path. The short travel required for moving from the transfer position to the working position allows for short delivery times and minimal mechanical wear.

Furthermore, the interface between the lens adapter and the transfer device can be designed with electrical contacts, e.g., for lens recognition, for lenses with integrated illumination, for lenses with an integrated camera (overview lens), or for motorized lenses. For example, the transfer device can contain contact pins and/or contact surfaces that establish electrically conductive contact with the contact pins or contact surfaces of the adapter when the adapter is moved into the working position or picked up in the transfer device.

Different lens adjustment lengths can be compensated for by using appropriately stored, retrievable, and adjustable Z-axis adjustments or by using different adapter lengths. Furthermore, the adapter can be designed for different lens interfaces, e.g., for different thread sizes and bayonet variants.

The highly dynamic positioning of the active objective can be achieved with a comparatively low mass and high rigidity, particularly of the transfer device. The drive components can be designed to be compact, lightweight, and cost-effective thanks to the favorable force ratios. Unlike with conventional objective turrets, the mounting positions of the individual objectives in the transfer element do not require high levels of accuracy. Thus, each individual objective holder in an assembled turret group must be extensively machined according to the state of the art in order to meet the high tolerance requirements during an objective change. In the case of the objective changing device according to the invention, only one objective holder of the transfer device needs to be aligned to the optical axis of the microscope system once. Each active objective always receives the same precise position in the microscope beam path via its adapter.

Conventional objective and nosepiece arrangements have disadvantages, for example, in three-dimensional imaging methods such as 3D sectioning, since maintaining a constant distance between the sample to be observed and the objective is rarely achieved. A changing distance has a negative impact on the quality of the image acquisition. The invention enables improved maintenance of such a constant distance.

The lens changing device according to the invention advantageously enables fast, precise and repeatable delivery of different lenses from the transfer position to the working position.

The object is further achieved by a method for delivering a and held in a lens holder into an optical axis of a microscope system. The method according to the invention comprises the steps of advancing a selected active lens into a transfer position, wherein an objective axis of the active lens in the transfer position does not coincide with the optical axis of the microscope system, and transporting the active lens from the transfer position along a transport path and in a transport direction substantially orthogonal to the optical axis of the microscope system to a working position by means of a transfer device. In this case, the objective axis of the active lens in the working position coincides with the optical axis of the microscope system. The length of the transport path is selected to be shorter than the extent of the lens holder in the transport direction, so that at least regions of the adapter of the active lens located at the working position are still located within the extent of the lens holder. In a further step, a controlled movement of the active lens located in the working position along the optical axis takes place to focus the active lens.

The method according to the invention can be preceded by selecting an active objective from a number of objectives.

In one embodiment of the method, the active lens is moved a distance parallel to the optical axis of the microscope system in the transfer position and then transported to the working position. As a result of this parallel movement, the active lens is released from the lens holder. The released active lens is thus unlocked and can be moved in the transport direction, in particular orthogonally to the optical axis of the microscope system.

• 1 eine schematische Darstellung eines Objektivs mit einem Adapter;
• 2 eine schematische Darstellung eines Objektivübergabeelements mit einem Objektiv mit Adapter an einer Übergabeposition;
• 3 eine schematische Darstellung einer Übernahmevorrichtung;
• 4 eine schematische Darstellung des Objektivs und der Übernahmevorrichtung mit Adapter in der Übernahmevorrichtung, Schlitten und DIC-Schieber;
• 5 eine schematische Darstellung des Objektivs und der Übernahmevorrichtung mit Abstreifer in der Übernahmevorrichtung;
• 6a und 6b eine schematische Darstellung einer Ausführung der erfindungsgemäßen Objektivwechselvorrichtung für eine aufrechte Anordnung 6a in einer seitlichen Ansicht und 6b in einer Ansicht von unten;
• 7a und 7b eine schematische Darstellung einer Ausführung der erfindungsgemäßen Objektivwechselvorrichtung für eine aufrechte Anordnung in einer Ansicht von unten, mit 7a: einem Adapter im vollständig eingeschobenen Zustand, und 7b: dem Adapter in einer Arbeitsposition;
• 8a bis 8d eine schematische Darstellung einer erfindungsgemäßen Objektivwechselvorrichtung in vier Betriebszuständen; 8a: während des Bestückens des Objektivübergabeelements; 8b: mit einem in die Übergabeposition zugestellten aktiven Objektiv; 8c: mit einem in die Arbeitsposition zugestellten aktiven Objektiv und 8d: mit einem fokussierten aktiven Objektiv und
• 9a bis 9d eine schematische Darstellung der Schritte zur Zustellung eines Objektivs aus einer Übergabeposition in eine Arbeitsposition: 9a mit einem Objektiv in der Übergabeposition; 9b dem Objektiv im angehobenen Zustand; 9c dem Objektiv in der Arbeitsposition und 9d dem Objektiv während einer Fokussierbewegung in Z-Richtung.

The invention is explained in more detail below using exemplary embodiments and figures. They show:

• 1 a schematic representation of a lens with an adapter;
• 2 a schematic representation of a lens transfer element with a lens with adapter at a transfer position;
• 3 a schematic representation of a transfer device;
• 4 a schematic representation of the lens and the transfer device with adapter in the transfer device, carriage and DIC slider;
• 5 a schematic representation of the lens and the transfer device with wiper in the transfer device;
• 6a and 6b a schematic representation of an embodiment of the lens changing device according to the invention for an upright arrangement 6a in a side view and 6b in a view from below;
• 7a and 7b a schematic representation of an embodiment of the lens changing device according to the invention for an upright arrangement in a view from below, with 7a: an adapter in the fully inserted state, and 7b: the adapter in a working position;
• 8a to 8d a schematic representation of an objective changing device according to the invention in four operating states; 8a: during loading of the objective transfer element; 8b: with an active objective moved into the transfer position; 8c: with an active objective moved into the working position; and 8d: with a focused active objective and
• 9a to 9d a schematic representation of the steps for moving a lens from a transfer position to a working position: 9a with a lens in the transfer position; 9b the lens in the raised state; 9c the lens in the working position and 9d the lens during a focusing movement in the Z direction.

The representations of the embodiments are exemplary and schematic. The same reference numerals designate the same technical elements unless expressly stated otherwise.

A lens 6 with an adapter 7 is in 1 shown as an example. The adapter 7 has a collar 73, which has flat contact surfaces at the top and bottom. In a base 75 of the adapter 7, there is a shaft 74 (see also 5 ), in which an optical element 8, here a DIC slider 8, can be inserted and held transversely to the lens axis 61. The DIC slider 8 can be removed from the shaft 74. On a base of the adapter 7, contact surfaces 71 and guide surfaces 72 are provided. The contact surfaces 71 serve to ensure a desired target positioning when this is aligned with corresponding adjustment surfaces 51 (see 3, 4 and 9a to 9d ) are in contact.

A lens transfer element or short transfer element 3 is in 2 as part of a lens changing device 2 (see 6 to 9 days ) and a microscope 1 (not shown in detail).

The transfer element 3 is designed as a revolver with four lens holders 4 in the form of forks 41. An adapter 7 with a lens 6 is held in one of the forks 41. The adapter 7 sits with a flat lower support surface of its collar 73 on the legs 42 of the respective fork 41. The ends of the forks 41 are directed towards each other for a short distance so that the forks 41 are slightly closed. This holds the adapter 7 in the lens holder 4 even when centrifugal forces occur. The transfer element 3 is rotatable about a central axis of rotation 31 by means of a drive 32 and a control unit 116 so that the individual lens holders 4 can be delivered to any position on their orbit. On the inner sides of the legs 42 pointing into the respective fork 41, guides 44 in the form of elevations are provided, which are designed to correspond to the corresponding guide surfaces 72 of the adapter 7 or the adapter 7 (see 3 ).

At least the ends of the legs 42 can be designed to be resilient in order to enable the adapter 7 to be pushed in or out laterally, whereby the spring force of the resilient ends must be overcome in each case.

3 shows an embodiment of a transfer device 5, on which a gripper 110, a drive 113 of the gripper 110, and a lens holder 53 for receiving a lens 6 provided with an adapter 7 are present. The gripper 110, which can be driven by the drive 113, can be moved back and forth along a transport direction TR and over a transport path TS (symbolized by a double arrow). When installed in the ready-to-use lens changing device 2, the transport direction TR is orthogonal to the optical axis 11 (see 5 and 8c ) of microscope 1.

The drive 113 is connected to the control unit 116 and can be controlled by it. The illustrated transfer device 5 is also equipped with a stripper 112, which is mounted on the gripper 110. The operation of the stripper 112 is explained below. 5 , 6a and 6b explained.

At least one adjustment surface 51 is provided in an area of the lens mount 53. An adapter 7 can be brought into contact with this adjustment surface by means of at least one correspondingly shaped contact surface 71 arranged on the adapter 7. When the contact surface 71 and the adjustment surface 51 are in contact, a desired position of the adapter 7 within the lens mount 53 is achieved. To ensure the correct positioning of the adapter 7 in the lens mount 53, guides 52 are provided on the lens mount 53 and guide surfaces 72 on the adapter 7, which correspond to one another.

The lens mount 53 is optionally provided with contact elements 118, which can each be designed as contact surfaces or as contact pins. An adapter 7 to be accommodated in the lens mount 53 can also have contact elements 118, which correspond in position, shape, and design to all or some of the contact elements 118 of the lens mount 53. Electrical control commands from the control unit 116 and/or information about current control states of the lens 6 and/or adapter 7 can be transmitted to the control unit 116 via the contact elements 118. Furthermore, a power supply to components of the lens 6, for example, motor drives and/or sensors, can be realized via the contact elements 118.

In the view of the adapter 7 and the lens 6, the optical element 8 inserted into the shaft 74 can be seen in its design as a DIC slider 8.

The movements of the gripper 110 are controlled by the interaction of the drive 113 and a cam disk 117 driven by the latter ( 4 ). The cam disc 117 engages with a driver in a corresponding recess of the gripper 110 and transmits a pushing or pulling movement to the gripper 110, which is thereby moved accordingly along the transport path TS.

The 5 The embodiment of the transfer device 5 shown is equipped with a carriage 9, which is guided on a carriage track 10 and driven in a controlled manner by means of a drive 120. The carriage 9 is provided with a magnet 111 in the form of a permanent magnet. The carriage 9 can be moved so close to an optical element 8, here the DIC slide 8, that the magnet 111 interacts with a magnetic region of the DIC slide 8 and a releasable holding force is present between the DIC slide 8 and the magnet 111. The magnetic region of the DIC slide 8 can be another magnet and/or a region suitable for magnetic interaction. For example, this region can consist of iron or contain iron.

In the 5 an adapter 7 is shown, which is inserted into the lens mount 53 (see e.g. 4 ) and whose covered and invisible contact surfaces 71 are connected to the also covered and invisible adjustment surfaces 51. For the sake of clarity, an objective 6 connected to the adapter 7 is not shown. The objective axis 61 of the objective 6 held in the desired position coincides with the optical axis 11 of the microscope 1. The drive 120 of the carriage 9 is designed in the example as a motor-driven toothed belt.

Both the drive 113 of the gripper 110, the drive 120 of the carriage 9 and a drive 119 for moving the transfer device 5 in the Z direction (hereinafter also: Z drive 119) and relative to a stand 115 of the lens changing device 2 are connected to the control unit 116 and can be controlled by it.

In order to enable precise and low-friction movement in the Z direction, guide elements 114 in the form of sliding, ball and/or roller guides are located between the transfer device 5 and the stand 115.

In 5 the DIC slider 8 is pulled out of the beam path of the microscope 1 and is no longer penetrated by the optical axes 11, 61. A portion of the DIC slider 8 is still located in the shaft 74. In order to use the DIC slider 8 for corresponding image recordings or to push the DIC slider 8 back into the adapter 7 so that, for example, the adapter 7 can be changed, the drive 120 is controlled by the control unit 116 and the carriage 9 is moved towards the adapter 7. If the DIC slider 8 is pushed into the adapter 7, the image recording can take place using the DIC method. If, on the other hand, the adapter 7 is to be changed, the drive 113 is controlled and the gripper 110 is moved in the transport direction TR. During this movement, the stripper 112 mounted on the gripper 110 is guided against the adapter 7 and the part of the optical element 8 protruding from the shaft 74, pushing the adapter 7 and the optical element 8 away from the transfer device 5. In doing so, the holding force between the magnet 111 and the optical element 8 is overcome, and the optical element 8 is released from the magnet 111. This embodiment is provided if the optical element 8 remains on the adapter 7 and is replaced together with it.

In a further embodiment, the optical element 8 is removed from the shaft 74 before changing the adapter 7 and remains on the carriage 9.

The carriage 9 can then be moved back to a position away from the lens mount 53 to prevent inadvertent coupling to a DIC slider 8 of an adapter 7 that is subsequently inserted into the lens mount 53. If the magnet 111 is an electromagnet, it is sufficient to switch it off.

A further embodiment of the lens changing device 2 according to the invention is shown in the two 6a and 6b shown. The lens changing device 2 is designed for an upright arrangement of the transfer element 3 and the receiving device 5.

The lens holders 4 are again designed as forks 41 (see 2 ), but have a further holding element 43. In the 6a and 6b In each case, one of the further holding elements 43 shown is shown in an open state and is therefore referred to as a further holding element 43o.

In the upright arrangement, an adapter 7 is inserted laterally into a gap 45 between the lens holder 4 - here designed as a fork 41 - and the respective further holding element 43. This can be designed in the form of a spring-loaded joint. When inserting the adapter 7, the further holding element 43 is held in place by the lateral pressure exerted by the adapter collar 73 (see 1 , 2 ) is opened. Once the adapter 7 is pushed into the final position in the lens holder 4, the lateral pressure on the additional holding element 43 decreases, and this element retracts around the collar 73. The adapter 7 and, if applicable, the lens 6 are thus securely held during movements of the transfer element 3.

One of the lenses 6, referred to here as the active lens 6a, is pulled into the lens receptacle 53 of the transfer device 5 by means of the gripper 110. Before the active lens 6a can be moved in the Z direction, for example, to focus it on an object plane, another element, such as a motor-driven lever, must act against the spring force of the additional holding element 43. The latter must be pressed open until the active lens 6a, in particular its adapter 7, is no longer locked by the additional holding element 43o and can be moved freely in the Z direction.

The ends of the fork legs 42 can be guided in grooves to hold the lenses 6 in the magazine against gravity.

In order to secure the adapter 7 against being thrown out during rotation of the lens holder 4, the adapter 7 and the lens holder 4 can each have at least one magnet 111. A magnetic force generated between the magnets 111 of the lens holder 4 and the The adapter 7 holds the adapter 7 against radial forces provided during operation of the lens mount 4. Alternatively, only the adapter 7 or the lens mount 41 has at least one magnet 111 if the respective counterpart is made of a (ferro-)magnetic material.

Alternatively, the additional retaining elements 43 can be designed as a spring-loaded catch. The adapter 7 is inserted into the respective lens mount 4 from below and must be moved via a spring-loaded catch. The spring force is dimensioned such that the mass of the respective lens 6 with the adapter 7 is held against gravity.

7a and 7b show an alternative embodiment of the further holding element 43. This is designed as a holding plate which is spaced apart from the lens holder 4 in the area of the fork 41, thus forming the gap 45 between the holding plate and the lens holder 4. The adapter 7 is inserted into the gap 45 with its collar 73 and rests with the collar 73 at least along sections of the collar 73 on the further holding element 43 ( 7a) .

The further holding element 43, designed as a holding plate, has projections 431 and/or partially circular cutouts 432 projecting into the opening of the fork 41. These correspond to the dimensions of the collar 73 such that the adapter 7, moved into the working position WP (symbolized by an arrow), can be guided past the further holding element 43 in at least one direction along the lens axis 61 ( 7b) .

Alternatively, one or more electromagnets can be used to hold the lenses 6 and/or adapters 7 in the lens holder 4. These are switched off as soon as the adapter 7 is clamped.

Alternatively, permanent magnets on adapter 7 and transfer element 3 can be designed so that their opposite poles face each other and attract each other. This holding force can be canceled by a movement, for example, perpendicular to the lens axis 61 or a rotational movement around the lens axis 61. The separation can be reinforced, for example, by additional magnets on the transfer element 3, which, after the movement, face magnets of the same polarity on the adapter 7. The resulting repulsive forces support the separation of adapter 7 and transfer element 3.

Based on the 8a to 8d and 9a to 9d The method for advancing an objective 6 provided with an adapter 7 and held in an objective holder 4 into the optical axis 11 of a microscope system 1 is described using the example of an inverse arrangement.

From a number of lenses 6 with adapters 7 held in the transfer element 3, one is selected as the active lens 6a ( 8a) The transfer element 3 is rotated about the rotation axis 31 by means of the drive 32 until the active objective 6a is advanced to a transfer position CP. The objective axis 61 and an optical axis 11 of the microscope 1 do not coincide, but are aligned parallel to each other. All objectives 6 and 6a held in the transfer element 3 are held in the objective holders 4 via their respective adapters 7 and secured against lateral movement. To clarify the invention, the transport path TS is shown with more than half the diameter of the objective 6.

The transfer device 5 is lifted in the Z direction by means of the Z drive 119 until the adapter 7 of the active objective 6a comes into contact with the transfer device 5 and the active objective 6a with its adapter 7 is lifted out of the objective holder 4 to such an extent that it can be moved in a transport direction TR essentially orthogonal to the optical axis 11 of the microscope 1 ( 8b) The transport distance TS traveled in this process is determined by the distance between the optical axis 11 and the lens axis 61. This lateral movement is possible because the adapter 7 of the raised lens 6 is slightly lifted out of the lens holder 4 by the transfer device 5 and/or an element blocking the lateral movement is opened.

The opened gripper 110 is extended so that it can reach behind the adapter 7 and pull it together with the active lens 6 in the transport direction TR and along the transport path TS from the transfer position CP into a working position WP ( 8c ). The active lens 6a is moved a relatively short transport distance TS, so that at least areas of the adapter 7 still remain within the extent of the lens holder 4. Contact surfaces 71 are guided against adjustment surfaces 51 of the lens holder 53 and are moved by the action of the gripper 110 and its drive 113 (see 3 , 4 , 5 ) are kept in contact with each other. In the working position WP, the objective axis 61 coincides with the optical axis 11 of the microscope system 1.

In order to adjust, in particular to focus, the active objective 6a located in the working position WP with respect to an object plane, the transfer device 5 is moved by means of the Z-drive 119 along the optical axis 11 of the microscope system Move tems 1 in the direction of the Z-axis Z until the desired setting is reached ( 8d ).

The 8a to 8d illustrate details of the processes when moving a lens 6 with adapter 7 from a transfer position CP to a working position WP. 9a shows the adapter 7 of the active lens 6a (not shown) in the lens holder 4 of the transfer element 3 in the transfer position CP. The lens axis 6.1 of the lens 6 located at the transfer position CP does not coincide with the optical axis 11.

The transfer device 5 is in 9b Moved in the direction of the Z-axis until the adapter 7 rests in the lens mount 53 and is lifted a short distance out of the lens holder 4. The lens axis 6.1 and the optical axis 11 are aligned parallel to each other, but do not coincide. The contact surfaces 71 of the adapter 7 and the adjustment surfaces 51 of the transfer device 5 are not in contact with each other. The open gripper 110 grips a contact surface 71 behind the adapter 7.

The 9c shows the adapter 7 after the gripper 110 has been driven in a controlled manner and the adapter 7 together with the active lens 6a (not shown here) has been moved along the transport path TS (see 8b) into the working position WP. In the working position WP, the lens axis 6.1 and optical axis 11 coincide.

9d This now schematically depicts the adapter 7 moving in the Z direction along the optical axis 11. This adapter is adjusted and clamped in the working position WP by the action of the gripper 110 as well as the contact surfaces 71 and adjustment surfaces 51. A spring, optionally attached to the gripper 110, presses the adapter 7 against at least one adjustment surface 51.

Reference symbol

1

Microscope system

11

Optical axis of the microscope system

2

Lens changing device

3

(Lens) transfer element

31

axis of rotation

32

Drive of the transfer element 3

4

lens mount

41

Fork

42

Legs/springy ends

43

additional holding element

431

projection

432

Excerpt

43o

additional holding element, open

44

guide

45

gap

5

Transfer device

51

Adjustment surface

52

Guide surface

53

Lens mount

6

lens

6a

active lens

61

lens axis

7

adapter

71

contact surface

72

Guide surface

73

Collar (of adapter 7)

74

shaft

75

base

8

optical element/DIC slider

9

Sleds

10

Toboggan run

110

gripper

111

magnet

112

scraper

113

Drive (Gripper 110)

114

Guide elements

115

tripod

116

Control unit

117

cam disc

118

Contact element

119

Drive Z-direction

120

Drive of the carriage 9

121

Feather

CP

Transfer position

WP

Working position

TS

Transport route

TR

Transport direction

Claims (10)

Objective changing device (2) for a microscope system (1) with an objective transfer element (3) with at least one objective holder (4) for holding an objective (6) provided with an adapter (7), wherein the objective transfer element (3) is designed to deliver a selected active objective (6) to a transfer position (CP) in a controlled manner, wherein an objective axis (61) of the active objective (6) in the transfer position (CP) does not coincide with the optical axis (11) of the microscope system (1), a transfer device (5) which is adjustable in the direction of the optical axis (11) of the microscope system (1) and which can be brought into contact with the adapter (7) of the active objective (6) and which is designed to transport the active objective (6) along a transport path (TS) in a transport direction (TR) orthogonal to the optical axis (11) of the microscope system (1) between the transfer position (CP) and a working position (WP) in the optical axis (11) of the microscope system (1); wherein the transport path (TS) is shorter than the extension of the lens holder (4) in the transport direction (TR), so that at least areas of the adapter (7) of the active lens (6) located at the working position (WP) are still within the extension of the lens holder (4). Lens changing device (2) according to Claim 1 , characterized in that the transfer device (5) is movable coaxially to the optical axis (11) of the microscope system (1) and is designed to lift the active objective (6) at the transfer position (CP). Lens changing device (2) according to Claim 1 or 2 , characterized in that the transfer device (5) has a gripper (110) which is designed to engage in the active lens (6), wherein the gripper (110) is displaceable in the transport direction (TR) and a lens holder (53) is provided which is designed as a transport path for the active lens (6) displaced by means of the gripper (110). Lens changing device (2) according to Claim 3 , characterized in that the lens holder (53) has adjustment surfaces (51) to which the active lens (6) can be placed with contact surfaces (71) of the adapter (7) designed to rest on the adjustment surfaces (51), wherein the respective active lens (6) resting on the adjustment surfaces (51) with the contact surfaces (71) is aligned parallel to the optical axis (11) of the microscope system (1). Lens changing device (2) according to one of the preceding claims, characterized in that each lens holder (4) has a locking device (43, 73), by the action of which the adapter (7) is locked in the lens holder (4) at least in a direction parallel to the optical axis (11). Lens changing device (2) according to one of the preceding claims, characterized in that the lens transfer element (3) has at least one lens holder (4) which is designed as a fork (41). Objective changing device (2) according to one of the preceding claims, characterized in that a carriage (9) is provided for coupling to an optical element (8) which is movable into the optical axis (11) of the microscope system (1) or out of the optical axis (11) of the microscope system (1). Lens changing device (2) according to Claim 7 , characterized in that the carriage (9) is provided with at least one magnet (111) or a mechanical coupling mechanism by means of which a releasable holding force can be generated between the carriage (9) and the optical element (8). A method for advancing an objective (6) provided with an adapter (7) and held in an objective holder (4) into an optical axis (11) of a microscope system (1), comprising the steps of: advancing a selected active objective (6) into a transfer position (CP), wherein an objective axis (61) of the active objective (6) in the transfer position (CP) does not coincide with the optical axis (11) of the microscope system (1); transporting the active objective (6) from the transfer position (CP) along a transport path (TS) and in a transport direction (TR) orthogonal to the optical axis (11) of the microscope system (1) to a working position (WP) by means of a transfer device (5), wherein the objective axis (61) of the active objective (6) in the working position (WP) coincides with the optical axis (11) of the microscope system (1), and the length of the transport path (TS) is selected to be shorter than the extent of the objective holder (4) in the transport direction (TR). such that at least areas of the adapter (7) of the active lens (6) located at the working position (WP) are still within the extent of the lens holder (4) and controlled movement of the active lens (6) located in the working position (WP) along the optical axis (11) for focusing the active lens (6). Procedure according to Claim 9 , characterized in that the active lens (6) in the transfer position (CP) has a distance parallel is moved to the optical axis (11) of the microscope system (1) and then transported to the working position (WP), whereby the active objective (6) is released from the objective holder (4) as a result of the displacement.